U.S. patent number 4,677,078 [Application Number 06/607,512] was granted by the patent office on 1987-06-30 for oxygen monitoring device and method.
This patent grant is currently assigned to Gould Inc.. Invention is credited to William Krug, Karl Minten.
United States Patent |
4,677,078 |
Minten , et al. |
* June 30, 1987 |
Oxygen monitoring device and method
Abstract
The present invention relates to a novel method and apparatus
which can provide continuous monitoring of the oxygen content of a
gas over an indefinite period of time and at a minimal cost. In the
novel apparatus of the present invention, a light source and a
light sensitive detector are disposed within the atmosphere to be
measured, and a polymeric film formed from a manganese tertiary
phosphine polymer complex is deposited between the light source and
the detector. As oxygen pressure increases or decreases a change in
color intensity of the film takes place which controls passage of
light from the light source to the detector. The detector in turn
is suitably connected to an audio and/or visual warning device
and/or a recorder which will provide the desired form of
warning.
Inventors: |
Minten; Karl (La Hoya, CA),
Krug; William (Hoffman Estates, IL) |
Assignee: |
Gould Inc. (Rolling Meadows,
IL)
|
[*] Notice: |
The portion of the term of this patent
subsequent to October 1, 2002 has been disclaimed. |
Family
ID: |
24432591 |
Appl.
No.: |
06/607,512 |
Filed: |
May 7, 1984 |
Current U.S.
Class: |
436/136; 422/87;
422/91; 436/164; 436/904 |
Current CPC
Class: |
G01N
21/783 (20130101); Y10T 436/207497 (20150115); Y10S
436/904 (20130101) |
Current International
Class: |
G01N
21/78 (20060101); G01N 21/77 (20060101); G01N
021/78 () |
Field of
Search: |
;436/151,136,164,167,904
;422/69,56,57,88,86,87,90,91 ;260/429R ;73/23,DIG.4 |
References Cited
[Referenced By]
U.S. Patent Documents
Other References
Hosseiny et al., Inorganica Chimica Acta, 39 (1980) 227-231. .
Clark, Jr., Trans. Amer. Soc. Artif. Intern. Organs, vol. 2, pp.
41-48 (1956). .
Bahmet et al, Anal. Chem., vol. 43, pp. 803-805 (1971). .
Hersch, Amer. Lab., (Aug. 1983), pp. 29-36. .
Janata et al., "Ion Selective Electrodes", in Freiser (ed),
Analytical Chemistry, vol. 2, pp. 124-126 (1980). .
Garverick et al., IEEE Trans. Electron Dev., vol. 29, pp. 90-94
(1982). .
Mins, III-Engineer's Notebook II, p. 87 (1982). .
Hlavey et al., Anal. Chem., vol. 49, No. 13, pp. 1890-1898 (1977).
.
McAuliffe et al, "Working Haem Analogues; Reversible Oxygenation of
the Manganese-Tertiary Phosphine Complexes MnLX.sub.2 ", JCS
Chemical Communications 1979, pp. 736-738 (1979)..
|
Primary Examiner: Turk; Arnold
Attorney, Agent or Firm: Walder; J. M. Sachs; E. E. Edgell;
G. P.
Claims
As our invention we claim:
1. Apparatus for monitoring the oxygen content in a stream of gas
comprising a housing means; a light source, and a light detection
means disposed within said housing means, and in alignment with
each other, said detection means being coupled to a warning device;
a film of manganese tertiary phosphine polymer complex disposed
between said light source and said light detection means; input
means by which the gas to be monitored is fed into said housing;
and egress means from said housing.
2. The apparatus according to claim 1 wherein the polymer in the
complex is silicone.
3. The apparatus according to claim 1 wherein said light source is
a LED light source.
4. The apparatus according to claim 1 wherein said polymer complex
is produced by the steps which comprise: forming a substantially
anhydrous first solution of a polymer selected from the group
consisting of polyvinylchloride, polystyrene, polyvinylacetate, and
silicone, dissolved in a suitable solvent; adding a substantially
anhydrous manganese salt of the formula:
wherein X is a species capable of forming an anion to form a second
solution, then adding to the solution of polymer and manganese salt
at least a stoichiometric equivalent with respect to said manganese
salt of a substantially anhydrous phosphine of the formula:
wherein R.sup.1, R.sup.2, and R.sup.3 may be the same or different,
and each is selected from the group consisting of substituted or
unsubstituted alkyl, cycloalkyl or aryl groups or hydrogen,
provided that no more than two of the groups R.sup.1, R.sup.2, and
R.sup.3 are substituted or unsubstituted aryl groups and that at
least one of the groups R.sup.1, R.sup.2, and R.sup.3 is a
substituted or unsubstituted alkyl, cycloalkyl or aryl group.
5. The apparatus according to claim 4 wherein X is a member
selected from the group consisting of chlorine, bromine, iodine and
thiocyanate, and said solvent is tetrahydrofuran.
6. The apparatus according to claim 4 wherein a stoichiometric
excess of phosphine is employed.
7. The apparatus of claim 4 wherein said phosphine is selected from
the group consisting of methyldialkylphosphines,
ethyldialkylphosphines, and pentyldialkylphosphines.
8. The apparatus of claim 4 wherein said polymer comprises between
about 2 and 30 wt.%, inclusive, of said first solution, the weight
ratio of said manganese salt to said polymer is in the range of
about 1:10 to 2:1, inclusive, and said phosphine is added in a
stoichiometric excess with respect to said manganese salt of
between about 50 and 150%, inclusive.
9. The apparatus of claim 8 wherein said polymer comprises between
about 5 and 20 wt.%, inclusive, of said first solution and said
weight ratio of said manganese salt to said polymer is between
about 1:2 and 2:1, inclusive.
10. The apparatus according to claim 4 wherein said phosphine is
selected from the group consisting of phenyldialkylphosphines,
diphenylalkylphosphines, cyclohexyldialkylphosphines,
dicyclohexylalkylphosphines, trialkylphosphines,
octyldialkylphosphines, and dodecyldialkylphosphines.
11. The apparatus according to claim 10 wherein said phosphine is
selected from the group consisting of trimethylphosphine,
triethylphosphine, tributylphosphine, methyldiethylphosphine,
ethyldimethylphosphine, dimethylphenylphosphine,
diethylphenylphosphine, methyldiphenylphosphine,
diphenylethylphosphine, and trioctylphosphine.
12. The apparatus according to claim 10 wherein said polymer is
polyvinylchloride.
13. A method of monitoring the oxygen content of a stream of gas
the steps which comprise passing the gas to be monitored through a
defined enclosed area, disposing a light source and light detection
means within said enclosed area and in alignment with each other,
disposing a film of manganese tertiary phosphine polymer complex
between said light source and said detection means, connecting said
detection means to a warning device whereby a drop in the oxygen
content in the gas stream will cause a reduction in the color
intensity of the said film permitting light to pass through the
film activating the light detection means and thereby activating
said warning device.
14. The method according to claim 13 where said polymer complex is
synthesized by the steps which comprise: forming a substantially
anhydrous first solution of a polymer selected from the group
consisting of polyvinylchloride, polystyrene, polyvinylacetate, and
silicone, dissolved in a suitable solvent; adding a substantially
anhydrous manganese salt of the formula:
wherein X is a species capable of forming an anion to form a second
solution; then adding to the solution of polymer and manganese salt
at least a stoichiometric equivalent with respect to said manganese
salt of a substantially anhydrous phosphine of the formula:
wherein R.sup.1, R.sup.2, and R.sup.3 may be the same or different,
and each is selected from the group consisting of substituted or
unsubstituted alkyl, cycloalkyl or aryl groups or hydrogen,
provided that no more than two of the groups R.sup.1, R.sup.2, and
R.sup.3 are substituted or unsubstituted aryl groups and that at
least one of the groups R.sup.1, R.sup.2, and R.sup.3 is a
substituted or unsubstituted alkyl, cycloalkyl or aryl group.
15. The method according to claim 14 wherein a stoichiometric
excess of phosphine is employed.
16. The method according to claim 14 wherein the polymer in the
complex is silicone.
17. The method according to claim 14 wherein said light source is a
LED light source.
18. The method of claim 14 wherein said phosphine is selected from
the group consisting of methyldialkylphosphines,
ethyldialkylphosphines, and pentyldialkylphosphines.
19. The method according to claim 14 wherein said solvent is
tetrahydrofuran.
20. The method according to claim 19 wherein X is a member selected
from the group consisting of chlorine, bromine, iodine and
thiocyanate.
21. The method of claim 14 wherein said polymer comprises between
about 2 and 30 wt.%, inclusive, of said first solution, the weight
ratio of said manganese salt to said polymer is in the range of
about 1:10 to 2:1, inclusive, and said phosphine is added in a
stoichiometric excess with respect to said manganese salt of
between about 50 and 150%, inclusive.
22. The method of claim 21 wherein said polymer comprises between
about 5 and 20 wt.%, inclusive, of said first solution and said
weight ratio of said manganese salt to said polymer is between
about 1:2 and 2:1, inclusive.
23. The method according to claim 14 wherein said phosphine is
selected from the group consisting of phenyldialkylphosphines,
diphenylalkylphosphines, cyclohexyldialkylphosphines,
dicyclohexylalkylphosphines, trialkylphosphines,
octyldialkylphosphines and dodecyldialkylphosphines.
24. The method according to claim 23 wherein said phosphine is
selected from the group consisting of trimethylphosphine,
triethylphosphine, tributylphosphine, methyldiethylphosphine,
ethyldimethylphosphine, dimethylphenylphosphine,
diethylphenylphosphine, methyldiphenylphosphine,
diphenylethylphosphine, and trioctylphosphine.
25. The method according to claim 23 wherein said polymer is
polyvinylchloride.
Description
BACKGROUND OF THE INVENTION
The present invention relates to a novel method and apparatus for
monitoring the level of oxygen in a feed stream or within the
atmosphere of a defined space such as an oxygen chamber, oxygen
tent, a room, or the like.
In the past there have been a number of procedures and apparatus
proposed for the monitoring or analysis or sampling of gases. These
include electrochemical methods, mass spectrometry methods, CHEMFET
devices, charger flow transistors, gas chromatographic and other
colorimetric procedures. In general, these involved extremely
expensive and sophisticated equipment and techniques or mechanisms
which were not truly reversible and/or indefinitely continuous. In
most cases, they relied on a chemical reaction by the gas which
would provide a corresponding change in pH thereby triggering a
color change in an indicator as a colorimetric chemical reaction
which was not quickly and fully reversible. Also, such systems were
obviously subject to the vagaries of other gases which might be
present particularly the relative amount of humidity present.
The earliest systems for monitoring of gases generally related to
gases such as carbon dioxide, hydrogen sulfide, halogens and the
like. These systems were colorimetric in nature, but the
colorimetric reaction was not immediately and completely self
reversing in response to a reversal of the change in concentration
of the gas being monitored.
As examples of one type of system taught by the prior art, mention
might be made of U.S. Pat. No. 3,754,867 Karl R. Guenther, in which
the carbon dioxide content of ambient air is monitored using a thin
layer of chemical which will absorb carbon dioxide forming an acid
which will provide a change in pH. An indicator present in the film
changes color. The system circumvents problems of humidity by using
an ionizing solvent having a vapor pressure in the range of 0-10 mm
at temperatures up to 150.degree. F., and compatible with the other
components of the system.
Another method is proposed by U.S. Pat. No. 3,114,610 to Gafford et
al., using very sophisicated analyzing equipment to measure the
particular presence of a constituent of a gas, which constituent
produces acidic or basic solutions. Again, basically a one-way
system in which the sample must be either neutralized, or the
indicator replaced, or the instrument recalibrated before further
sampling can continue.
U.S. Pat. No. 2,232,622 to Moses et al., and U.S. Pat. No.
2,741,544 to Chaikin et al., provide an alternate method in which
continuous sampling is possible over a finite period of time. Moses
et al., relates to the monitoring of hydrogen sulfide, and Chaikin
et al., relates to the apparatus of fluoride analysis. They are,
however, very similar methods, in that continuous analysis over a
finite period of time is achieved by winding forward a continuous
strip of tape impregnated with the indicator. As with Guenther and
Gafford, however, the system relies on a change in pH to trigger a
color change in an indicator.
All of the foregoing systems have certain basic limitations. They
can only measure gases which provide an acidic or basic solution
such as carbon dioxide, hydrogen sulfide, halogen, or the like; and
they are operable, at best, intermittently or over a relatively
finite period of time. In addition, those which do provide for some
measure of continuous monitoring, such as Moses et al., involve
very cumbersome and relatively expensive apparatus, such as a drive
motor and the like.
The range of oxygen detection methods is large but generally very
sophisticated and more expensive than those described above and
includes such diverse means as electrochemical reactions and cells,
optical fiber monitors based on fluorescence quenching of dyes or
colorimetric oxygen reactions, CHEMFETS and charge-flow transistor
devices, anaerobic bacterial activity, mass spectrometry, gas
chromatography and the addition of odorants of other detectable
trace gas additives to the oxygen supply. However, use of most such
techniques is far from commercialization, while others are suitable
only for certain limited applications. None of these techniques
provide an inexpensive continuous simple procedure for in-line
monitoring of oxygen level in a fuel stream or enclosed area.
The Clark cell [L. C. Clark, Jr., Trans. Amer. Soc. Artif. Intern.
Organs, 2, 41-48 (1965)] is the most commonly used electrometric
oxygen sensor available today. It is based on polarographic
principles by which, for a given applied voltage, the current
between two electrodes is directly proportional to the oxygen
partial pressure in the environment.
A very similar polarographic monitor has also been developed by
Hersch [W. Bahmet and P. A. Hersch, Anal. Chem., 43, 803 (1971) and
P. A. Hersch, Amer. Lab, Aug. 1973, p. 29] and is based on the
linear variation of the limiting current attainable from a
cadmium-air cell when the partial pressure of oxygen is varied.
There are two very major problems with such electrochemical
methods, they depend on the precise maintenance of solution
concentration, and they depend upon a kinetically limited gas
liquid equilibrium system. One can speculate optical methods since
these methods could theoretically be based on any colorimetric
oxygen reaction.
Mass spectrometry and gas chromatography, however, are the methods
conventionally used for the quantitative and qualitative analysis
of gases, and could easily be adapted to oxygen monitoring. A major
consideration in their use, however, would be their relative cost
and size. A detector based specifically on the paramagnetic
properties of oxygen is also conceivable, but seems even less
promising than mass spectrometry or gas chromatography on the basis
of cost, size and versatility. Thus, simple optical systems are
purely speculative, while instrumental procedures are too complex
and too expensive.
Transistor devices have also been suggested. CHEMFET devices have
been proposed for monitoring systems. Use of these chemically
sensitive field effect transistor devices [J. Janata and R. H.
Huber, in "Ion-Selective Electrodes", Analytical Chemistry, Vol. 2,
H. Freiser, ed., Plenum Press, New York, 1980, pp. 124-6] is
predicated on the measurement of changes in the source/drain
current passing through a transistor due to variations in the
electric field in the gate region of the device. The observed
changes in current could, for example, result from the absorption
of oxygen on, or its reaction with, material, in the gate region of
the device.
Charge-flow transistors have also been suggested. Application of
these devices [S. L. Garverick and S. D. Senturia, IEEE Trans.
Electron Dev., 29, 90 (1982)] involves the measurement of the
change in admittance (AC conductance) of a transistor resulting
from the adsorption of a given species (e.g. O.sub.2) on, or its
reaction with, a resistive material placed in the gate region of
the device. The admittance of the device is directly related to the
time delay observed between the application of a gate-to-source
voltage and the initiation of the source-to-drain current. Both
CHEMFET devices and charge-flow transistors tend to be very complex
systems overall, and yet are very unreliable.
None of the teachings heretofore available provide a truly
inexpensive and completely reliable apparatus andor method by which
the oxygen content of a gas or atmosphere can be continuously and
reversibly monitored over an indefinite period of time using
nondepletable materials and, insofar as the monitoring element, no
moving parts. It will be appreciated that a serious need exists to
monitor the oxygen content of a gas feed stream or the atmosphere
within a container, chamber, room, or the like, to maintain
continuous monitoring with instantaneous warning in the event of an
undue pressure drop. Such systems and apparatus would have
particular utility and applicability in medical applications, such
as monitoring the oxygen feed to a patient and/or the oxygen
content of the atmosphere within an oxygen tent or room. Such
monitoring is now possible, if at all, only using extremely
cumbersome and expensive equipment.
IN THE DRAWINGS
FIG. 1 is a schematic illustration of one embodiment of the present
invention.
FIG. 2 is a schematic diagram of the circuitry of a device suitable
for use in the practice of the present invention.
SUMMARY OF INVENTION
We have now discovered a novel method and apparatus which can
provide continuous monitoring of the oxygen content of a gas over
an indefinite period of time and at a minimal cost. The method and
apparatus of our invention provides an instantaneous response to
critical changes in oxygen level independent of the level of
humidity, and without the need for the use of pH sensitive
indicators, or expensive and sophisticated analytical
instruments.
FIG. 1 is a schematic diagram of the apparatus of the present
invention including defined area 1 having input port 2 by which gas
is fed into said area, and egress means 3 by which gas may leave
the area. Disposed within said area is a light source 4 and a light
detection means 5 is shown coupled to a warning device 6, a
manganese tertiary phosphine polymer complex 7 is deposited between
said light source and said light detection means.
In the novel apparatus of the present invention, a light source and
a light sensitive detector are disposed within the atmosphere to be
measured, and a polymeric film formed from a manganese tertiary
phosphine polymer complex is deposited between the light source and
the detector. The detector in turn is suitably connected to an
audio and/or visual warning device and/or a recorder which will
provide the desired form of warning.
Applicants' co-pending, commonly assigned application Ser. No.
607,513 filed May 7, 1984, now U.S. Pat. No. 4,544,707 discloses
and claims certain novel manganese tertiary phosphine polymer
complexes.
The manganese tertiary phosphine polymer complexes are prepared by
adding a manganese salt to an anhydrous solution of a polymer
selected from the group consisting of polyvinylchloride, silicone,
polyvinylacetate, and polystyrene, in a suitable solvent, then
adding a monodentate ligand to the polymer-manganese salt solution.
These polymer compositions will reversibly complex with gases such
as oxygen. The manganese salt corresponds to the formula:
wherein X is a species capable of forming an anion; and the ligand
is a compound of the formula:
wherein R.sup.1, R.sup.2, and R.sup.3 may be the same or different,
and is selected from the group consisting of substituted or
unsubstituted alkyl, cycloalkyl or aryl groups or hydrogen,
provided that at least one of the groups R.sup.1, R.sup.2, and
R.sup.3 is a substituted or unsubstituted alkyl, cycloalkyl or aryl
group.
While elevated temperatures may be required to dissolve the
starting polymer in the solvent such as tetrahydrofuran the
remainder of the synthesis can generally be carried out at room
temperature, though preferably under anhydrous conditions. The
polymer content of the starting polymer solution can vary widely
and is primarily dependent on the amount of solvent needed to
maintain suitable handling conditions such as any desired viscosity
or the like. A 2% to 30% by weight solution is generally considered
operable, and a 5% to 20% by weight solution is preferred.
The weight ratio of manganese salt to starting polymer is usually
in the range of about 1:10 to 2:1 and preferably about 1:2 to 2:1.
The ligand is added as at least a stoichiometric equivalent of the
manganese salt, and preferably as a stoichiometric excess of 50% to
150%.
Ligands of particular interest include those within the following
groups:
Phenyldialkylphosphines, diphenylalkylphosphines,
cyclohexyldialkylphosphines, dicyclohexylalkylphosphines,
trialkylphosphines, including methyldialkylphosphines,
ethyldialkylphosphines, pentyldialkylphosphines,
octyldialkylphosphines, and dodecyldialkylphosphines. The following
specific ligands are generally regarded as of interest,
trimethylphosphine, triethylphosphine, tributylphosphine,
methyldiethylphosphine, ethylimethylphosphine,
dimethylphenylphosphine, diethylphenylphosphine,
methyldiphenylphosphine, diphenylethylphosphine, trioctylphosphine,
in which the alkyl group is preferably a straight chain alkyl
group.
A film can be cast from the solution of the polymer composition by
any of a variety of widely known techniques well known to those
skilled in the art. Once the film is cast, as it absorbs oxygen the
intensity of the color of the film will change getting darker or
more intense as more oxygen is absorbed--or lighter as the process
is reversed and oxygen is released. The particular color evidenced
by a given film produced from a polymer composition containing a
given ligand will vary according to the specific X moiety
employed.
By casting a film inside a tube used to conduct oxygen to a
hospital patient, it is possible to monitor oxygen supply using a
photosensitive metering device which can be triggered by a change
in oxygen concentration of the gas being delivered to the patient.
If the concentration of oxygen were to drop below a predetermined
critical limit, there would be a change in the color intensity of
the film, in this case becoming lighter, which would permit
transmission of a sufficient intensity of light to reach the
photosensitive metering device, thereby triggering suitable
alarms.
PREFERRED EMBODIMENT
The preferred polymer compositions for use with the present
invention are prepared with ligands of the formula:
wherein R.sup.1 and R.sup.2 may be the same or different, and each
is selected from the group consisting of alkyl and substituted
alkyl moieties having 1 to 12, preferably 2 to 18 carbon atoms; and
R.sup.3 is selected from the group consisting of alkyl and
substituted alkyl moieties having 1 to 12, preferably 2 to 18
carbon atoms and aromatic moieties having from 6 to 18 and
preferably 6 to 10 carbon atoms.
EXAMPLE 1
O.sub.2 Gas Sensor
A film was cast from a complex of
tri-n-butylphosphine-THF-PVC-manganese (II) thiocyanate which was
prepared as described in example 2 of co-pending application Ser.
No. 607,513 filed May 7, 1984, now U.S. Pat. No. 4,544,707.
A freshly prepared 1".times.1" film of the complex
tri-n-butylphosphine-THF-PVC-manganese (II) thiocyanate was
sandwiched between two 2".times.3" Lexan plastic blocks. These
blocks were bolted together to form the detection cell. Air flowed
across the film in the cell via a 1/4" diameter channel bisected by
the two cell halves. In one block on one side of the film a green
LED source (Radio Shack No. 276-022) was mounted. Opposite the
source on the other side of the film in the adjacent block a CdS
photocell detector (Radio Shack 276-116) was mounted. To eliminate
stray light the entire cell was painted and further covered with
black electrical masking tape.
For experimental evaluation, the level of pO.sub.2 in argon was
varied. Breathable levels of pO.sub.2 give the film the deepest red
color and a maximum electrical resistance across the photocell. As
the pO.sub.2 decreases, the film color lightens. More illumination
from the LED is transmitted across the film to the photocell
detector causing the electrical resistance across it to decrease.
Depending on LED intensity, film thickness, and pO.sub.2 the
photocell resistance can vary from 100 ohm to 100 Kohm.
EXAMPLE 2
Oxygen Level Change Alarm
The oxygen gas sensor described in example 1 was integrated into an
inexpensive alarm system that provides a warning that the pO.sub.2
level has changed. A piezoelectric speaker (Radio Shack No.
273-064) provided an audible alarm while a yellow to red LED (Radio
Shack No. 276-035) provides a visual alarm.
The photocell was incorporated into a programmable light meter
circuit as illustrated by FIG. 2, [Engineer's Notebook II, A
Handbook of Integrated Circuit Applications, by Forest M. Mins,
III, First Edition, 1982, page 87] at PC1, R1 and R3 are external
potentiometers with a variable resistance from 1 Kohm to 1 Mohm. In
operation, for a given level of pO.sub.2, LED source light
intensity, and film thickness, the resistance across PC1 is
constant. Both R1 and R3 are adjusted until the alarm signals
cease. If the pO.sub.2 level changes, the photocell resistance
changes. Using the aforementioned circuit, the result is both an
audible buzzing and a change in LED color from yellow to red. This
signals the change in pO.sub.2 level measured by the gas
sensor.
In general the manganese thiocyanate-PVC-phosphine polymer
compositions were found to provide the most "heme-like" films, and
their moisture insensitivity seemed to increase with the chain
lengths of trialkyl substituted phosphines. This is to say, polymer
compositions, where the ligand was trioctyl phosphine, showed
better moisture insensitivity than those in which the ligand was
tributyl phosphine, which in turn showed better moisture
insensitivity than compositions prepared using triethyl phosphine.
In addition polymeric compositions, wherein the starting polymer
was silicone showed better moisture insensitivity than polymer
compositions prepared using PVC or polystyrene. Polymeric
compositions, wherein the starting polymer was polystyrene, tended
to exhibit greater color intensity at low oxygen concentrations,
which might make them particularly useful in application wherein it
is necessary to be alerted to even relatively low concentrations of
oxygen.
While we are not willing to limit ourselves to any one theory by
which the novel method, compositions, or properties of our
invention might be explained, it would appear likely that some type
of crosslinking or complexing is taking place between two or more
of the manganese salt, the phosphine, the tetrahydrofuran and/or
the starting polymer. It would also appear that the significantly
improved rates of absorption and desorption of gas exhibited by the
films prepared from the novel polymer compositions of the present
invention may be attributable to a significantly increased exposed
surface area of gas complexing agent, as compared to the exposed
surface area of prior art materials such as those employed by
McAuliffe et al., as coating on a particulate support.
Alternatively, the ligand, polymer, manganese halide, and solvent
complex may alter the activation barrier or energetics for gas
absorption and desorption by the heme analogue.
The compositions of the present invention may be used in any form,
shape, or configuration in which the starting polymer is
conventionally employed, using any conventional casting technique.
It has been noted that one of the most obvious use of the novel
polymer compositions of the present invention, would be in the form
of a film. It will be understood by those skilled in the art, that
the specific conditions under which the film is to be cast, the
techniques employed in laying down the film, and the environmental
and other conditions under which the film will be employed, may
require the use of other and additional materials such as heat, or
light stabilizers, wetting agents and other similar additives well
known to those skilled in the art. Suitable additives may be
combined with the novel compositions of the present invention
without substantially altering the advantages set forth
hereinbefore.
It will be course also be obvious that other changes, modifications
and alterations can be made in the compositions and methods herein
described without departing from the scope of the invention herein
disclosed and it is our intention to be limited only by the
appended claims.
* * * * *